1Professor of Civil Engineering, College of Engineering, Andhra University, Visakhapatnam, India
2Research Scholar, Department of Civil Engineering, College of Engineering, Andhra University, Visakhapatnam, India
Online published on 30 January, 2020.
Reinforced earth technique is being extensively used in construction of various civil engineering structures over the last two decades. The design and performance of reinforced soil structures depend mainly on the fill material interaction with the reinforcing material. Granular soils (frictional fills) are preferred in construction of reinforced soil structures, particularly in reinforced earth retaining walls and reinforced soil beds as they mobilise higher interfacial friction with reinforcing materials and the interfacial friction is not much affected in presence of moisture. Cost of conventional granular fill material namely sand and moorum has increased due to scarcity arising from continuous dependence. As the cost of reinforced earth retaining walls is largely affected by cost of fill material, efforts are being made to explore cost effective materials particularly non hazardous industrial wastes as fill material. Rock flour and Coal ashes have been tried to some extent in construction of reinforced earth walls based on the efforts of researchers. In this direction, the present work is aimed at exploring the potential of copper slag (a by-product from the matte smelting and refining of copper) for use as backfill/fill material in retaining structures. The previous studies on copper slag revealed that it is non hazardous and is a coarse grained material with good frictional characteristics, the suitability of the copper slag for use in conventional and reinforced earth (soil) retaining walls is assessed based on laboratory studies. Apart from evaluation of engineering properties of copper slag, it's interaction with woven geotextile fabric is evaluated from modified shear box and pullout tests. The results of the study indicated the potential of the copper slag for use as backfill material in conventional retaining walls and as fill in reinforced earth retaining walls. Copper slag has exhibited better interaction with woven geotextile as it mobilised angle of interfacial friction equal to its angle of internal friction as sand mobilises angle of interfacial friction of the order of 0.75 to 0.9 times the angle of internal friction.
Reinforced Earth, Retaining Wall, Frictional Fill, Interfacial friction angle, Copper slag, Woven geotextile, Pull out test, modified shear box test
